Case of Isolated Absence of the Azygos Vein: Evaluation Using Photon-counting Detector CT.

The isolated absence of the azygos vein was incidentally found on computed tomography (CT) examination in a 60-year-old female. The exact anomaly can be evaluated on high-resolution images of 0.4-mm slice thickness with low keV using photon-counting detector CT. The azygos vein, including the azygos arch, was absent, and a mildly dilated hemiazygos vein flowed to the left brachiocephalic vein through the left superior intercostal vein. A hemiazygos vein connected the left renal vein at the level of the first lumbar vertebra. This patient was the second patient to undergo evaluation using volume rendering images. High-resolution maximum-intensity projection images were useful for assessing the anatomy. Radiation dose was decreased compared with that in conventional CT.

Evaluation of Incidental Findings on Abdominopelvic CT: Potential Benefit of Photon-counting Detector CT Over Conventional Single-energy CT.

PURPOSE: To assese of potential benefint of photon-counting detector CT (PCD-CT) over conventional single-energy CT (CSE-CT) on accurate diagnosis of incidental findings with high clinical significance (IFHCS). MATERIALS AND METHODS: This retrospective study included 365 patients who initially underwent abdominopelvic contrast-enhanced CT (AP-CECT) without non-enhancement (PCD-CT: 187 and CSE-CT: 178). We selected IFHCS and evaluated their diagnosability using CE-CT alone. IFHCSs that could not be diagnosed with only CE-CT were evaluated using additional PCD-CT postprocessing techniques, including virtual non-contrast image, low keV image, and iodine map. A PCD-CT scanner (NAEOTOM Alpha, Siemens Healthineer, Erlangen, Germany) was used. RESULTS: Thirty-nine IFHCSs (PCD-CT: 22 and CSE-CT: 17) were determined in this study. Seven IFHCSs in each group were able to diagnose with only CE-CT. Fifteen IFHCSs were able to diagnose using the additional PCD-CT postprocessing technique, which was useful for detecting and accurately diagnosing 68.2% (15/22) of lesions and 65% (13/20) of patients. All IFHCSs were accurately diagonosed with PCD-CT. CONCLUSION: PCD-CT was useful for characterizing IFHCSs that are indeterminate at CSE-CT. PCD-CT offered potential benefit of PCD-CT over conventional single-energy CT on evaluation of IFHCS on only abdominopelvic CT.

Partial splenic embolisation using n-butyl cyanoacrylate: intraprocedural evaluation by magnetic resonance imaging.

OBJECTIVES: To evaluate the use of diffusion-weighted imaging (DWI) for estimating infarcted splenic volume during partial splenic embolisation (PSE) using n-butyl cyanoacrylate (NBCA). METHODS: Twenty consecutive patients (57.2 ± 11.7 years) with hypersplenism underwent PSE. Intrasplenic branches were embolised using NBCA via a 2.1-French microcatheter aiming at infarction of 50 to 80 % of total splenic volume. Immediately after PSE, signal intensities (SI) of embolised and non-embolised splenic parenchyma were measured on DWI. Semi-automated volumetry (SAV) on DWI was compared with conventional manual volumetry (MV) on contrast-enhanced CT 1 week after PSE. Platelet counts were recorded before and after PSE. RESULTS: The SI on DWI in the embolised parenchyma decreased significantly (P < 0.01) to 24.7 ± 8.1 % as compared to non-embolised parenchyma. SAV and MV showed a strong correlation (r = 0.913 before PSE, r = 0.935 after PSE, P < 0.01) and significant (P < 0.01) reduction of normal splenic volume was demonstrated on both SAV (71.9 ± 12.4 %) and MV (73.6 ± 9.3 %) after PSE. Based on the initial SAV, three patients (15 %) underwent additional branch embolisation to reach sufficient infarction volume. Platelet counts elevated significantly (522.8 ± 209.1 %, P < 0.01) by 2 weeks after PSE. No serious complication was observed. CONCLUSION: Immediate SI changes on DWI after PSE allowed semi-automated splenic volumetry on site. KEY POINTS: • Partial splenic embolisation (PSE) is an important interventional technique for hypersplenism • Diffusion-weighted MR reveals an immediate decrease in signal in the embolised parenchyma • Such signal reduction permits semi-automated splenic volumetry on site. • This allows precise quantification of the amount of parenchyma infarcted, avoiding additional PSE.

A case of incomplete duplication of the portal vein associated with multiple congenital anomalies.

Double portal veins are a duplication of the portal vein and normal portal vein with an accessory portal vein. We report a case of a 63-year-old asymptomatic female with double portal veins. There was fat accumulation observed in the area which was supplied by the first portal vein in normal position, and fatty sparing of the liver was observed in the area which was supplied by the second portal vein in the preduodenal position. The 2 portal veins were equal in size. Furthermore, the patient presented with multiple congenital anomalies, including double inferior vena cava, splenic lobulation, and accessory liver lobe. Therefore, double portal veins in our case were thought to be an incomplete duplication of the portal vein with multiple congenital anomalies.

Carbon dioxide (CO2) vs iodinated contrast digital subtraction angiography during balloon-occluded retrograde transvenous obliteration (BRTO) using foam sclerosant for gastric varices.

PURPOSE: To compare the visualization of the target gastric varices (GV) on balloon-occluded retrograde transvenous venography (BRTV) using iodinated contrast material vs carbon dioxide (CO(2)) in preparation for subsequent balloon-occluded retrograde transvenous obliteration (BRTO) using foam sclerotherapy. MATERIALS AND METHODS: In 16 consecutive patients with nonruptured GV, BRTV was performed first using iodinated contrast material and then with CO(2). BRTV was repeated whenever there were changes in the catheter or patient position or when coil embolization of collaterals was needed. Each visualization grade of GV (grade 1 = GV only; grade 2 = GV > collaterals; 3 = GV < collaterals; grades 4-5 = collaterals only) was determined by two observers in consensus. During foam BRTO, the GV visualization grade was recorded again and confirmed by C-arm computed tomography (CT). RESULTS: In 38 pairs of BRTV, GV grades were significantly (P < .0001) lower (ie, favoring BRTO) on CO(2) BRTV (mean ± standard deviation, 1.8 ± 0.8) than on iodine BRTV (3.4 ± 0.8). GV grades on foam BRTO (1.4 ± 0.7) were similar to the grades obtained on the most recent CO(2) BRTV (1.3 ± 0.5) but were significantly smaller (P < .0001) than on iodinated BRTV (3.1 ± 0.9). GV were opacified by foam on initial C-arm CT in 14 patients (87.5%), and complete thrombosis of GV was obtained without any complication in all 16 patients (100%). CO(2) reached the GV even when iodinated contrast material could not (grade 4) in seven of our 16 patients (43.8%), leading to successful BRTO. CONCLUSIONS: CO(2) BRTV visualized GV better than did iodine BRTV and changed the management of more than 40% of patients by enabling successful foam BRTO in patients in which conventional liquid BRTO could not be performed.

Study of the association between an anomalous superior vena cava and horseshoe kidney.

BACKGROUND: The incidence of inferior vena cava anomalies in patients with horseshoe kidney is higher than that reported in the general population. As far as we know, no studies have reported the incidence and variations of superior vena cava (SVC) anomalies using multidetector-row computed tomography (MDCT) in patients with horseshoe kidney. METHODS AND RESULTS: Using MDCT, 71 patients with a horseshoe kidney (group A: 45 males, 26 females; mean age, 60.1 ± 10.2 years) and 2,292 patients without a horseshoe kidney (group B: 1,385 males, 907 females; mean age, 61.1 ± 13.5 years) were retrospectively evaluated for the incidence and variations of SVC anomalies, and the incidence of an anomalous SVC was compared between groups. An anomalous SVC was identified in 3 group A patients (4.2%) (double SVC, n=2; persistent left SVC without a right SVC, n=1) and 5 group B patients (0.22%) (double SVC, n=3; persistent left SVC without a right SVC, n=2). MDCT revealed a significantly higher incidence of anomalous SVC in patients with a horseshoe kidney than in those without a horseshoe kidney (P<0.001). CONCLUSIONS: Patients with horseshoe kidney frequently have an anomalous SVC. Although the incidence of horseshoe kidney is related in some way to that of an anomalous SVC, the reasons for their coexistence remain unclear.

Major venous anomalies are frequently associated with horseshoe kidneys.

BACKGROUND: Several cases of horseshoe kidney with anomalous inferior vena cava (IVC) have been described, but there have been no reports of the incidence and variation of anomalous IVC in patients with horseshoe kidneys detected using multidetector row computed tomography (MDCT). METHODS AND RESULTS: 105 patients with horseshoe kidneys were evaluated with MDCT and a variety of venous anomalies were identified in 30 patients (28.6%). Anatomical variations of the renal vein were identified in 24 patients (22.9%), which was no higher than the reported incidence in the general population. However, variations of the IVC were identified in 6 patients (5.7%), which was a higher incidence than expected to be found in the general population: 1 pre-isthmic IVC with retrocaval ureter, 2 double IVCs posterior to the horseshoe kidney, 2 left IVCs posterior to the horseshoe kidney, and 1 azygos continuation of the IVC. CONCLUSIONS: Horseshoe kidneys are frequently found in patients with other venous, and particularly IVC, anomalies, which should be evaluated using MDCT as part of treatment planning.

Delayed Enhancement of Ascites after Iodine Contrast Administration Assessed with Dual-energy Computed Tomography: A Case Report.

We report a case of 71-year-old woman with lung cancer and high-attenuation ascites (HAA) due to iodine contrast material (ICM). The patient underwent two sequential CT scans at interval of 4 h between examinations by using ICM. The second scan was obtained by dual-energy CT (DE-CT), yielding the virtual non-contrast (VNC) image and iodine map, which were used to evaluate HAA. The VNC image revealed ascites with water density, and HAA was thought to contain iodine because the attenuation of ascites around the liver was similar to that of the spleen on the iodine map. The VNC image and iodine map using DE-CT were useful in differentiating HAA due to iodine (delayed enhancement of ascites) from hemorrhagic ascites in this patient.

C-arm CT-guided foam sclerotherapy for the treatment of gastric varices.

The authors describe here the use of foam sclerotherapy under C-arm computed tomography (CT) guidance for the treatment of gastric varices via balloon-occluded retrograde transvenous obliteration in seven patients and percutaneous transhepatic obliteration in one patient. All gastric varices were occluded successfully after replacement of blood by foam, which was trapped in the gastric varices as shown by C-arm CT. It also helped reduce the amount of sclerosant, an issue that is associated with severe complications, such as hemolysis, allergy, acute respiratory distress syndrome, and others. Foam sclerotherapy under C-arm CT guidance is a promising tool in the therapeutic armamentarium against gastric varices.

18F-FDG Uptake of Localized Malignant Peritoneal Mesothelioma.

We present 2 cases of malignant peritoneal mesothelioma (MPM) characterized by a localized solid mass without ascites and showing F-FDG uptake. A 79-year-old man with a history of asbestos exposure suffered from an epithelioid MPM originating from the hepatoduodenal ligament with FDG uptake (SUVmax 16.8). Another 80-year-old man with esophageal cancer showed desmoplastic MPM of the small bowel mesentery with FDG uptake (SUVmax 4.0). Desmoplastic MPM is more aggressive and yields poorer prognosis compared with the epithelioid type. However, the present desmoplastic MPM case showed mild FDG uptake because of rich fibrosis.

A case of intrahepatic splenosis: usefulness of splenic scintigraphy.

We report a 39-year-old male with intrahepatic and peritoneal splenosis, focusing on scintigraphic findings. Dynamic computed tomography (CT) showed a 3 cm lesion in the posterior right lobe of the liver with strong early phase enhancement that was homogenous to the liver enhancement in the late phase. A few enhancing nodules were also found in the peritoneum. On gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced dynamic magnetic resonance imaging (MRI), the hepatic lesion had abnormal signal on diffusion-weighted imaging, high signal intensity on T2-weighted imaging, and early enhancement with accumulation decline in the hepatocyte phase. CT and MRI findings of the hepatic lesion were similar to normal spleen. To rule out hepatic neuroendocrine tumor and peritoneal metastases, somatostatin receptor scintigraphy was performed and showed tracer accumulation in the hepatic lesion, which we considered a false positive. Splenic scintigraphy using Tc-99 m-phytate showed accumulation in the hepatic lesion and peritoneal nodules. Given the patient's history of splenic injury and splenectomy 15 years prior and the current imaging findings, we highly suspected splenosis. After surgical treatment, the patient was pathologically diagnosed with intrahepatic and peritoneal splenosis. Splenosis should be suspected when a patient has a history of trauma or abdominal surgery. Since intrahepatic splenosis presents as a nonspecific hypervascular lesion on CT and MRI, splenic scintigraphy should be considered in these patients. In addition Tc-99 m-phytate scintigraphy is easy to use and cost-effective.

Persistent left superior vena cava with absent right superior vena cava in adults: CT and clinical findings.

PURPOSE: Persistent left superior vena cava (PLSVC) with absent right superior vena cava (ARSVC) is rare. We evaluated CT and clinical findings of adults with ARSVC. MATERIALS AND METHODS: Our study included 11 adults with ARSVC (mean age, 63 ± 17 years). We evaluated CT findings of the azygos vein system and coronary sinus (CS) using thin slice data of > 64 MDCT. Arrhythmia and congenial heart disease were assessed. We compared the CS diameters between the ARSVC group and the control group of 120 adults with normal vena cava (mean age, 60 ± 4 years). RESULTS: Adults with ARSVC had no azygos vein arch and the hemiazygos vein continued to PLSVCs via the superior intercostal vein. Eight adults had arrhythmia including conduction disturbance and one arrhythmia was associated with atrial septal defect. All adults with ARSVC had dilated CS larger than 11 mm. The mean diameter of the CS in the ARSVC group was 18.4 mm, and that of the control group was 6.8 mm. CS diameter in the ARSVC group was larger than that in the control group (p < 0.001). CONCLUSION: Adults with ARSVC had dilated CS and no azygos vein arch. Four adults had conduction disturbance.

Cutaneous Metastases from Testicular Diffuse Large B-cell Malignant Lymphoma and Bowen Disease: 18F-FDG PET-CT Findings.

Here, we report the case of cutaneous metastases from testicular diffuse large B-cell malignant lymphoma (DLBCL) concurrent with Bowen disease evaluated with 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT). A 60-year-old male underwent orchiectomy to remove his left testicle because of DLBCL. Multiple skin lesions appeared 1 month postoperatively. Furthermore, an intractable erythematous plaque localized to the right lower leg was present from 2 years before the operation. 18F-FDG PET-CT images revealed multiple skin lesions with marked FDG uptakes in the face, neck, and thigh of this patient, as well as a lower leg lesion with minimal FDG uptake. Biopsy of both lesions revealed cutaneous metastases from DLBCL and Bowen disease (BD) of the lower leg lesion. 18F-FDG PET-CT images following chemotherapy and resection of BD demonstrated no FDG uptake.

Aberrant Left Brachiocephalic Vein versus Persistent Left Superior Vena Cava without Bridging Vein in Adults: Evaluation on Computed Tomography.

Objective: Persistent left superior vena cava without bringing vein (PLSVC w/o BV) is a common thoracic venous anomaly, while aberrant left brachiocephalic vein (ALBCV) is an uncommon condition. We compared the incidences of the two venous anomalies and assessed congenital cardiovascular diseases (CCDs) in adults using computed tomography (CT). Materials and Methods: We reviewed the recorded reports or CT images of 49,494 adults for PLSVC w/o BV and ALBCV in two hospitals. We determined incidences of two venous anomalies and the rate of associated CCDs. Results: 76 PLSVCs w/o BV and 27 ALBCVs were found. The incidence of PLSVC w/o BV was 0.15% and the incidence of ALBCV was 0.055%. PLSVC w/o BV had higher incidence than ALBCV (p<0.001). Four PLSVCs w/o BV and one ALBCV were associated with congenital heart diseases. Two PLSVCs w/o BV and four ALBCVs were associated with congenital aortic arch anomaly (CAAA). ALBCV had higher incidence of associated CAAA than PLSVC w/o BV (P=0.02). Conclusion: The incidence of ALBCV was <50% that of PLSVC w/o BV. The two venous anomalies found on CT during adulthood were rarely associated with CCDs.

Right Aortic Arch with Mirror-image Branching in Adults: Evaluation Using CT.

OBJECTIVE: We evaluated radiological findings and clinical significance of right aortic arch with mirror-image branching (RAMI) in adults using data from computed tomography (CT) examinations. MATERIAL AND METHODS: We reviewed recorded reports and CT images obtained from university and branch hospitals for RAMI in adults. The RAMI incidence in adults found on CT was assessed. Associated congenital and acquired cardiovascular diseases were evaluated. RESULTS: A total of 27 cases (14 men, 13 women; mean age, 59.4 ± 18.3 years) of RAMI were found. Among 107,014 cases in three hospitals, the RAMI incidence in the first, second, and third Tokai University hospitals were 0.018%, 0.012%, and 0.012%, respectively. Eight cases had high aortic arches and four cases had aortic diverticulum (AD) in proximal descending aorta. Three cases had a history of tetralogy of Fallot. One case with an absent left pulmonary artery and three cases with an aberrant left brachiocephalic vein were found incidentally. Two cases were associated with AD aneurysm and vascular ring formation. One case had stenosis of the left subclavian artery due to injury. CONCLUSION: Cases of RAMI found in CT examinations in adults were extremely rare. Some cases were associated with congenital anomalies and/or acquired cardiovascular disease.

Multicenter investigation of the incidence of inferior vena cava filter fracture.

PURPOSE: Inferior vena cava filter fracture (FF) may cause life-threatening complications, including cardiac tamponade, although the actual prevalence remains unclear. Therefore, we investigated the incidence of FF. MATERIALS AND METHODS: Data on fracture incidence with filter brands, filter positions [suprarenal (SR) vs. infrarenal (IR)], and follow-up durations were collected from the databases of eight hospitals. RESULTS: Of 532 patients, Günther Tulip (GT), Trap/OptEase (TE/OE), ALN and VenaTech (VT) were implanted in 345, 147, 38 and 2 patients, respectively. Of these, filter retrieval was attempted in 110 (21.7%) patients and was successful in 106 (96.4%). Of the remaining 426 patients, FFs were observed in two (0.7%) of 270 GT filters and 19 (14.1%) of 135 TE/OE filters. Fragment embolization occurred in one patient with a GT filter (50.0%) and three with a TE/OE filter (15.8%) with a total follow-up interval of 718.0 ± 1019.4 days. FF occurred more frequently in TE/OE than in GT filters (p < 0.001). Kaplan-Meier estimates showed significantly higher fracture-free rates for GT than TE/OE (p < 0.001) and IR-TE/OE than SR-TE/OE (p < 0.05). CONCLUSIONS: TE/OE filters are not suitable for permanent implantation due to the relatively early and high fracture rates.

Congenital anomalies of the left brachiocephalic vein detected in adults on computed tomography.

PURPOSE: Anomalous left brachiocephalic vein (BCV) is a rare and less known systemic venous anomaly. We evaluated congenital anomalies of the left BCV in adults detected during computed tomography (CT) examinations. MATERIALS AND METHODS: This retrospective study included 81,425 patients without congenital heart disease who underwent chest CT. We reviewed the recorded reports and CT images for congenital anomalies of the left BCV including aberrant and supernumerary BCVs. The associated congenital aortic anomalies were assessed. RESULTS: Among 73,407 cases at a university hospital, 22 (16 males, 6 females; mean age, 59 years) with aberrant left BCVs were found using keyword research on recorded reports (0.03%). Among 8018 cases at the branch hospital, 5 (4 males, 1 female; mean age, 67 years) with aberrant left BCVs were found using CT image review (0.062%). There were no significant differences in incidences of aberrant left BCV between the two groups. Two cases had double left BCVs. Eleven cases showed high aortic arches. Two cases had the right aortic arch, one case had an incomplete double aortic arch, and one case was associated with coarctation. CONCLUSION: Aberrant left BCV on CT examination in adults was extremely rare. Some cases were associated with aortic arch anomalies.

The Apparent Diffusion Coefficient (ADC) as a Potential Marker of Inflammation Associated with Body Abscesses.

OBJECTIVE: To assess the feasibility of apparent diffusion coefficient analysis in evaluating the inflammatory severity of extracranial abscesses. METHODS: This retrospective study included 23 patients with solitary body abscesses (except those in the brain) who underwent 1.5-T diffusion-weighted magnetic resonance imaging (DWI) at b-values of 0 and 1000 s/mm2. Three types of the Apparent Diffusion Coefficient (ADC) measurements of abscesses were performed: the mean ADC value in region of interest (ROI), volume of interest (VOI), and histogram analysis of the ADC distribution in the VOI. Furthermore, two different areas were used: high-intensity area on b = 0 and b = 1000 s/mm2 images. Subsequently, correlations between ADC data and C-reactive protein (CRP) levels were assessed using Pearson's correlation coefficient (R) analyses. RESULTS: The strongest correlation was observed between the mean ADC value in VOI and CRP level (R = 0.78, P < 0.01), followed by ROI (R = 0.77, P < 0.01) by using the high-intensity area on the b = 0 s/mm2 images. CONCLUSION: The mean ADC value in the ROI encompassing the abscess at a b-value of 0 s/mm2 may be useful to assess the inflammatory activity of an abscess in daily practice.

Congenital tracheoesophageal fistula successfully diagnosed by CT esophagography.

Tracheoesophageal fistula (TEF) or bronchoesophageal fistula may be congenital, inflammatory, neoplastic, or secondary to trauma. Congenital TEF or bronchoesophageal fistula is usually associated with esophageal atresia and is readily diagnosed in infancy. But if it is not associated with esophageal atresia, it may persist until adulthood. Some theories have been proposed to explain this delay in diagnosis. We present a case of a 70-year-old man with congenital TEF. The TEF was successfully diagnosed by multidetector-row CT esophagography.